Hand instrument for electrolytic and acid etching



Oct. 10, 1967 H. P. WOLFER 3,346,477

HAND INSTRUMENT FOR ELECTROLYTIC AND ACID ETCHING Filed June 8, 1964 2 Sheets-Sheet 2 INVENTOR. Hoe/W301 P, 71 544252 United States Patent 3,346,477 HAND INSTRUMENT FOR ELECTROLYTIC AND ACID ETCHING Harnisch P. Wolfer, Studio City, Calif., assignor to W 8: W

Products, Lakewood, Calif., a partnership composed of Donald Whaley and Lillian F. Wolfer Filed June 8, 1964, Ser. No. 373,182

14 Claims. (Cl. 204224) This invention relates to apparatus for the development and detection of strain areas on metal surfaces. Such apparatus may be used, by way of example, to reveal obliterated stamped impressions, such as serial numbers.

Known laboratory apparatus of this character utilizes a process of electrolytic acid etching. Apparatus of this character is bulky and not portable. Yet there is a substantial need for the use of such apparatus in the field. Thus time may not allow for sending the object to a laboratory, or the object may be unduly bulky. Accordingly, the primary object of this invention is to provide a compact battery-operated hand instrument that can be conveniently carried on the person.

Experience has shown that the proper surface treatment of metals for these purposes requires different acids and various acid strengths. Another object of this invention is to provide a hand instrument of this character cooperable with replaceable cartridges for various metals.

In order properly to etch a metal surface, the metal surface itself is polarized, and a circuit is completed through an acid electrolyte applicator engaging the surface. The applicator must be continuously moved in order to prevent any localized current flow. Another object of this invention is to provide a hand instrument having means for continuously moving the applicator.

Still another object of this invention is to provide a device of this character that incorporates a light for indicating that the etching process is progressing.

Still another object of this invention is to provide a unique replaceable acid electrolyte cartridge.

Still another object of this invention is to provide an instrument of this character that compactly packages replaceable components.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several embodiments of the invention. For this purpose, there are shown a few forms in the drawings accompanying and forming part of the present specification, and which drawings, unless as otherwise indicated, are approximately true scale. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a pictorialview of a hand instrument incorporating the present invention;

FIG. 2 is an enlarged axial sectional view of the instrument;

FIG. 3 is a fragmentary view similar to FIG. 2 and illustrating the manner in which the contents of the cartridge are expressed;

FIG. 4 is a pictorial view of the cartridge;

FIG. 5 is an axial sectional view of a full cartridge;

FIG. 6 is a fragmentary sectional view illustrating a modified cartridge structure;

FIG. 7 is an axial sectional view of another modified form of the present invention; and

FIGS. 8 and 9 are enlarged transverse sectional views taken along planes corresponding to lines 8-8 and 9-9 of FIG. 7.

In FIG. 1 there is illustrated a hand instrument 10 V 3,346,477 Patented Oct. 10, 1967 adapted to be used for treating the surface of a work piece W. Mounted in the barrel or tubular body 11 (FIG. 2) are a battery 12 and an electrolyte cartridge 13. A bulbous cap 14 made of translucent material is press fitted in one open end of the body 11. The other end of the body is closed by a tip 15 that has a screw-threaded or friction connection with the body 11.

The cartridge 13 includes a container tube 16 made of polyethylene material having like properties of flexibility and resilience. One end of the tube is closed. The tube 16 contains a quantity of acid electrolyte solution B that flows through an electrode 17 press fitted in the other end of the tube 16. The electrode 17 has an elongated passage 18 for this purpose. The passage opens at the bottom of a recess located at the end of the electrode 17. The passage 18 is normally closed by a small integral plug located at the inner end of the passage 18, as shown in FIG. 5. When the cartridge is to be used, a rod is inserted into the passage 18 and the plug is broken. The electrode 17 is made of compacted carbonaceous material or the like that is adequately frangible for this purpose.

Fitted in the recess 19 is a felt or synthetic applicator 20 that receives the electrolyte passed through the passage 18. The applicator 20 has a head that provides a shoulder engaging the end surface of the electrode 17.

The cartridge also includes a conductive strip 21 (FIG. 4) that extends along the outside of the tube 16. One end of the conductor strip 21 is clamped to the electrode 17 at a place adjacent the end of the tube 16. For this purpose a clamping ring 22 is provided. The end of the conductor strip 21 is caught between the ring and the electrode. The other end of the conductor strip 21 extends across the closed end of the tube 16 and is bent so as to form a spring contact cooperable with the end of the battery 12.

The battery 12 and the cartridge 13 are both held in the barrel by the tip 15. The tip has a stepped bore 23. The electrode 17 fits the bore 23 and projects through it. The shoulder formed by the stepped bore 23 engages a shoulder 24 formed on the electrode 17 whereby outward movement of the electrode is stopped.

As the tip 15 is screwed into position, the cartridge 13 is moved upwardly, and the spring end of the strip 21 in turn urges the battery upwardly toward the cap 14. The battery terminal engages the central terminal of a small lamp 25, and determines the position of the battery 12. In the assembled position, the spring end of the strip 21 is slightly flexed.

The lamp 25 is mounted in an open-ended screw socket 26. The socket 26 in turn is mounted by an insulation disk 27 press fitted in the cap 14. The bulb of the lamp is located in the bulbous part of the cap 14, and its terminal is positioned at the end of the barrel 11.

The electrolyte E, flowing to the felt applicator 20, may 'be applied to the work W. In order to provide electrolytic decomposition of the work surface, a circuit is completed through the work W. For this purpose analligator clip 28 (FIG. 1) is clamped to the work W. A lead 29, extending through a small aperture 30 in the body 11, connects the alligator clip to the socket 26. Accordingly a circuit is completed from the upper terminal of the battery 12, through lamp 25, lead 29, clip 28, Work W, electrolyte in the applicator 20,electrode 17, strip 21 to the lower opposite terminal of the battery 12.

In order to assist the flow of electrolyte to the tip 20, the tube 16 may be squeezed by the application of digital pressure. In order to transfer digit pressure from the exterior of the instrument barrel 11 to the tube 16, a plunger 31 is provided. The plunger 31 is mounted at the end of a leaf spring 32 in turn riveted to the case 11 as at 33. The plunger 31 extends through a lateral aperture 34. When the finger of the user engages the plunger 31, it is moved inwardly against the side of the tube 16, and the tube is equeezed and electrolyte expressed. When digital pressure is released, the tube returns to its normal configuration, drawing air into the tube.

The lamp 25 indicates the flow of current through the work W.

a As the instrument is used, the operator moves the applicator 20 along the work, and the surface is slowly etched and in turn, makes visible any strain areas.

The cartridge 41 shown in FIG. 6 is similar to the cartridge 13 except that in this instance the cartridge tube 42 is made of thin metal or other conductive material. In this instance the strip 21 is not needed. The tube 42 is sufiiciently flexible and resilient to operate in the same manner.

The instrument 51 as shown in FIG. 7 incorporates a motor 52 for continuously moving the felt or synthetic applicator 53 of a cartridge 54 similar to the cartridge 41.

The instrument case 55, made in this instance of conductive material, has a partition wall 56 intermediate its length. Extending in one direction from the partition wall 56 is an elongate barrel 57 adapted to receive the car- 'tridge 54. Attached to the threaded end of the barrel 55 is a tip 58 removable for purposes of access to the barrel. Formed at the opposite end of the instrument 51 is a cup 59. The motor 52 which is encapsulated fits into the bottom of the cup, and a series of batteries 60 fit in the top of the cup. The motor shaft 62 projects through an aperture 63 in the transverse wall 56 and into the bottom or inner end of the barrel 55. Contactor disks 64 and 65 fit the cup and accommodate the batteries between them. These disks may be made of insulation board with conductive segments riveted thereto to provide suitable connections. The upper contactor disk 65 has a central terminal 66 that engages the central terminal of a lamp 67. The lamp 67 is accommodated in a screw-threaded socket 68 mounted on a cap 69 by a disk 70. A lead 71 for an alligator clip (not shown) extends through an access aperture 72 in the cap and is suitably connected to the socket 68.

The cartridge 54 includes a tube 74 received in a rotary socket member 75 carried by motor shaft 62. A resilient compressible pad 76 is located in the bottom of the socket.

The outer end of the cartridge tube carries an electrode 77 provided with a passage 78 for outward flow of electrolyte. The electrode 77 has an intermediate shoulder as at 79 that engages the inner race of a small ball bearing structure 80. The ball bearing structure 80 in turn seats against shoulder 81 formed in the cap 58. The ball bearing 80 supports the cartridge for rotation about the axis of the device. Furthermore, the bearing 80 serves as a brush to establish electrical contact with the electrode 77 and the electrolyte contained in the tip 53.

Some of the batteries 60 are used for the purpose of polarizing the work W. For this purpose the contactor 64 has a peripheral part in electrically conductive relationship to the case 55. This part polarizes the case whereby the electrode 77 is at a negative potential. The work W is oppositely polarized by the alligator clip attached to the lead 71 and connection provided by the contactors 64 and 65.

The remaining batteries 60 are used to operate the motor 52 to impart rotation to the felt applicator 53. The motor is controlled by a switch 82 mounted in a recess 83 formed in a longitudinally extending rib 84 on the side of the barrel 55. The recess 83 is located substantially at the middle of the barrel 55 and at a place where the hand of the user would normally be situated. The switch 82 has an actuator 85 projecting through an aperture 86 in the rib 84. A twin lead 87 extends from the side of the recess 83 upwardly through the rib. One of the twin conductor leads is connected to the motor 52 and the other to the contactor disk 64. A short lead connects another part of the contactor disk 65 to the motor 52. Accordingly, upon operation of the switch 82, an energization circuit for the motor is established.

Adjacent the actuator of the switch 82 is a plunger 88 used to constrict the cartridge tube 74. The plunger 88 has a base 89 that overlies the edges at the inner end of an access aperture 90 to keep it in place.

In the present form, the applicator 53 may be continuously rotated, ensuring appropriate etching of the work W.

The inventor claims:

1. In a cartridge for a hand etching instrument:

a tube made of resilient flexible materials;

an electrode secured at one end to one end of the tube;

an applicator detachably secured to the other end of the electrode;

said electrode having a passage, one end of the passage being closed by the applicator and the other end extending to a point closely adjacent but short of the said one end of said electrode, said electrode being frangible whereby the passage may be placed in communication with the interior of the tube by forcing a rod through the passage.

2. In a hand etching instrument:

a hollow casing having a barrel;

a motor in the casing and having a shaft;

a seat member carried on the shaft;

a removable electrolyte cartridge in the barrel having a closed end and an open end with its closed end detachably and frictionally supported by the seat member;

said cartridge having an electrode at its open end; and

a tip detachably secured to the end of the barrel and having bearing means for supporting the electrode for rotation of the cartridge.

3. In a hand etching instrument:

a hollow casing having a barrel;

a motor in the casing and having a shaft;

a seat member carried on the shaft;

a removable acid electrolyte cartridge in the barrel .Wlth its inner end supported by the seat member;

said cartridge having an electrode at its outer end;

'an electrically conductive tip detachably secured to the .end of the barrel and having bearing means for supporting the electrode for rotation of the cartridge;

battery means carried by the casing;

means connecting the tip and said electrode to one terminal of the battery means;

a lead connected to the other terminal of the battery means; and

means connecting the battery to the motor.

4. In a hand etching instrument:

a casing;

a removable electrolyte container held in the casing and having a closed end and an open end;

an electrode secured to the open end of the container;

an applicator carried by the electrode and exposed at the end of the casing;

means supporting the container for rotation about an axis extending through the applicator;

a motor carried by the casing and having a shaft;

an axially separable coupling between the closed end of the container and said shaft for rotating the container; and

battery means carried in the casing for polarizing the electrode and for operating the motor.

5. In a hand etching instrument:

a casing;

an acid electrolyte container made of flexible resilient material and held in the casing;

an electrode secured to the container;

an applicator carried by the electrode and exposed at the end of the casing;

means supporting the container for rotation about an axis extending through the applicator;

a motor carried by the casing for rotating the container;

' battery means for' polarizing the electrode and for operating the motor; and

means mounted on the casing for transferring digital pressure to the container.

6. In a hand etching instrument:

a casing;

an acid electrolyte container made of flexible resilient material and held in the casing;

an electrode secured to the container;

an applicator carried by the electrode and exposed at the end of the casing;

means supporting the container for rotation about an axis extending through the applicator;

a motor carried by the casing for rotating the container;

battery means for polarizing the electrode and for operating the motor;

means mounted on the casing for transferring digital pressure to the container; and

switch means for the motor and biased to open position, said switch means having an actuator located adjacent the pressure transferring means.

7. In a hand etching instrument:

a casing;

an acid electrolyte cartridge having a tube, said cartridge having an electrode secured at one end of the tube and an applicator attached to the electrode, said electrode having passage means for conducting electrolyte to the applicator;

a detachable tip carried by the casing and mounting the cartridge for rotation about its axis with the applicator exposed at the end of the casing;

a motor in the casing for rotating the cartridge; and

battery means in the casing for operating the motor and for polarizing the electrode, said tip being made of conductive material and engaging said electrode to serve as a brush therefor.

8. In a hand etching instrument:

a casing;

an acid electrolyte cartridge having a tube made of flexible resilient material, said cartridge having an electrode secured at one end of the tube and an applicator attached to the electrode, said electrode having passage means for conducting electrolyte to the applicator;

a detachable tip carried by the casing and mounting the cartridge for rotation about its axis with the applicator exposed at the end of the casing;

a motor in the casing for rotating the cartridge;

battery means in the casing for operating the motor and for polarizing the electrode; and

means mounted on the casing for transferring digital pressure to the container.

9. In a hand etching instrument:

a casing;

an acid electrolyte cartridge having a tube made of flexible resilient material, said cartridge having an electrode secured at one end of the tube and an applicator attached to the electrode, said electrode having passage means for conducting electrolyte to the applicator;

a detachable tip carried by the casing and mounting the cartridge for rotation about its axis with the applicator exposed at the end of the casing;

a motor in the casing for rotating the cartridge;

battery means in the casing for operating the motor and for polarizing the electrode;

means mounted on the casing for transferring digital pressure to the container; and

switch means for the motor and biased to open position, said switch means having an actuator located adjacent the pressure transferring means.

10. In a hand etching instrument:

(a) a hollow casing having axially separable parts providing access to the interior of the casing, said casing parts having opposed end Walls; the end wall of one of said parts carrying a contact member and the end wall of the other of said parts having a restricted aperture;

(b) electrical cell means accommodated in one end of said casing and having terminals at opposite ends, one of said terminals being positioned to engage said contact member, and the other of said terminals being located intermediate the ends of said casing;

(c) an electrolyte cartridge unit detachably received in the other end of said casing in tandem with said cell means, said cartridge unit including:

(i) a tube for containing electrolyte, said tube having an integrally formed Wall for closing one end of said tube, the other end of said tube being open,

(ii) an electrode member secured at one end of said open end of said tube, the other end of said electrode member being reduced and projecting through said restricted aperture of the other of said casing parts, said electrode member having an axial passage,

(iii) an applicator carried at the said projecting end of said electrode member to receive electrolyte from said tube via said passage,

(iv) a conductive strip extending along the side of said tube with one end in electrical conductive relationship to said electrode member and the other end extending across the closed end of said tube and bent to form a spring contact to engage the other terminal of said cell means; the effective free axial length of said spring contact being slightly greater than the difference between the effective interior length of said casing and the combined eitective length of said cartridge unit and said electrical cell means whereby said spring is flexed to ensure electrical contact; and

(d) a lead connected to said contact member for completing an electrical etching circuit through the work and said applicator.

11. The combination as set forth in claim 10 in which said tube is flexible; and means for transferring digital pressure through the side of said casing to the side of said tube for expressing electrolyte to said applicator.

12. In a hand etching instrument:

(a) a hollow casing having axially separable parts providing access to the interior of the casing, said casing parts having opposed end walls; the end wall of one of said parts carrying a contact member and the end wall of the other of said parts having a restricted aperture;

(b) electrical cell means accommodated in one end of said casing and having terminals at opposite ends, one of said terminals being positioned to engage said contact member, and the other of said terminals being located intermediate the ends of said casing;

(c) an electrolyte cartridge unit detachably received in the other end of said casing in tandem with said cell means, said cartridge unit including:

(i) a tube for containing electrolyte, said tube having an integrally formed wall for closing one end of said tube, the other end of said tube being open, said tube being made of electrical conductive material,

(ii) an electrode member secured at one end to said open end of said tube, the other end of said electrode member being reduced and projecting through said restricted aperture of the other of said casing parts, said electrode member having an axial passage,

(iii) an applicator carried at the said projecting end of said electrode member to receive electrolyte from said tube via said passage,

(iv) a compression spring made of electrically conductive material interposed between said closed end of said tube and said other terminal 7 8 of said cell means; the efiective 'free axial length References Cited of said compression spring being sli htly greater than the difference between the eif'eztiv'e interior UNITED STATES PATENTS lenght of said casing and the combined eifec- 2,612,649 10/1952 Banks 15 552 tive length of said cartridge unit and said elec- 5 trical cell means whereby said compression FOREIGN PATENTS spring is flexed to ensure electrical contact, and 155,313 3/ 1954 Australia- (d) a lead connected to said contact member for c'orn- 665, 5/1929 Francepleting an electrical etching circuit through the Work 3,087 12/ 1904- Great Britain. and said applicator. 10 469,437 7/1937 Great Britain. 13. The combination as set forth in claim 12 in which said tube is flexible; and means for transferring digital OTHER REFERENCES pressure through the side of said casing to the side of Mester et al. German application 1,130,245 printed said tube for expressing electrolyte to said applicator. May 24, 1962. (K1. 48a, 15/ 1902).

14. The combination as set forth in claim 1 together 15 with a conductive strip having one end clamped to said JOHN MACK, primary Examiner, electrode and its other end bent across the other end of i said tube and bowed to form a spring contact, said strip VALENTINE, Assistant Examine"- interrnediate its ends extending along the side of said tube. 

9. IN A HAND ETCHING INSTRUMENT: A CASING; AN ACID ELECTROLYTE CARTRIDGE HAVING A TUB MADE OF FLEXIBLE RESILIENT MATERIAL, SAID CARTRIDGE HAVING AN ELECTRODE SECURED AT ONE END OF THE TUBE AND AN APPLICATOR ATTACHED TO THE ELECTRODE, SAID ELECTRODE HAVING PASSAGE MEANS FOR CONDUCTING ELECTROLYTE TO THE APPLICATOR; A DETACHABLE TIP CARRIED BY THE CASING AND MOUNTING THE CARTRIDGE FOR ROTATION ABOUT ITS AXIS WITH THE APPLICATOR EXPOSED AT THE END OF THE CASING; A MOTOR IN THE CASING FOR ROTATING THE CARTRIDGE; BATTERY MEANS IN THE CASING FOR OPERATING THE MOTOR AND FOR POLARIZING THE ELECTRODE; MEANS MOUNTED ON THE CASING FOR TRANSFERRING DIGITAL PRESSURE TO THE CONTAINER; AND SWITCH MEANS FOR THE MOTOR AND BIASED TO OPEN POSITION, SAID SWITCH MEANS HAVING AN ACTUATOR LOCATED ADJACENT THE PRESSURE TRANSFERRING MEANS. 